Fix counts on issues dashboard (#2215)

* Fix counts on issues dashboard

* setupSess -> setupSession

* Unit test

* Load repo owners for issues

routers/api/v1/repo/issue.go

@@ -31,6 +31,7 @@ func ListIssues(ctx *context.APIContext) {
 	issues, err := models.Issues(&models.IssuesOptions{
 		RepoID:   ctx.Repo.Repository.ID,
 		Page:     ctx.QueryInt("page"),
+		PageSize: setting.UI.IssuePagingNum,
 		IsClosed: isClosed,
 	})
 	if err != nil {